High TTFB on Certain IP Address Block

[tcoomer]

One IP address block is much slower to load pages, have a TTFB of ~10-15 seconds on many websites some are hosted on Cloudflare.

While another public IP address block is what should be expected ~ <1ms speed of TTFB when loading web pages.

The only thing that changes when loading the pages is the public IP address block that the IP address is contained within. The DNS, firewall, private IP address, etc. are the same. Just the public IP addressing changes.

Any idea on what the cause is? How can this be fixed?

[sdayman]

To get a better feel for how widespread the issue is, you can do a global timing test:
https://performance.sucuri.net

It also helps to find out which datacenter those requests are going to:
https://example.com/cdn-cgi/trace (but for your real domain)

And a traceroute might help as well:
https://support.cloudflare.com/hc/en-us/articles/200169336-How-do-I-run-a-traceroute-

[tcoomer]

Oh - yeah. According to this, the response time for this is way higher than it should be (assuming I am reading that report correctly).

.327 ms is the avg for first byte in Atlanta, US